A bird-strike accident refers to an occurrence that arises due to the collision of a flying aerocraft such as aircraft with a flying bird in the sky. With a rapid development of the civil aviation industry, the bird-strike accident of the civil aircraft becomes one of the most severe safety and security threats of the civil aviation. As shown in the related report of the UA (United Airlines), during the period of 1990 to 2008, U.S. civil aviation reported 89,727 accidents caused by the collision of animals with the civil aircrafts, and 97.4% of these accidents are caused by flying birds. Related data show that the windward side of the aircraft, including the windshield, the radome, the engine, the wing leading edge and the tail leading edge of the aircraft, is the position which is most easily struck by birds. The interior of the leading edge structure is usually provided with oil circuit system or control wiring system, and disastrous accidents can hardly be avoided once those internal facilities are destroyed by the bird strike. Thus, it counts for much to resolve the problem of anti-bird strike performance of the tail leading edge of aircraft. It is explicitly prescribed in Paragraph 631 in Article 25 of the Airworthiness Standard of Transport Aircraft issued by the CAAC that the design of structure for an aircraft tail must ensure that the aircraft, after encounter of collision with a bird of 3.6 kilograms (8 pounds), can still fly and land safely, and the speed of the aircraft during the collision is equal to the cruising speed of the aircraft at a selected sea level. Some research indicates that the bird represents predictable hydromechanical behavior under a high speed strike.
At present, most of the designs of the anti-bird strike with respect to the tail leading edge adopt a high-strength composite material and a simple sandwich structure. Most of the design ideas present the function and shape with sacrificial structure so as to be deformed as far as possible to absorb the energy of the bird strike. In addition, taking a vertical tail leading edge structure mentioned by Alessandro Airoldi, et al. in related documents as an example, the outer surface of this structure is made from an aluminum alloy material, and the interior of this structure is made from a carbon fiber composite material. In the experiment, a bird of 4 pounds is used to strike the structure at a speed of 270 knots, and the structure is obviously destroyed. M. A. McCARTHY, et al. issue a wing leading edge structure having the leading edge skin being the FML composite material. In the experiment, the structure bears the strike of a bird of 4 pounds at a speed of 200 m/s, and the leading edge is not broken down but deformed tremendously. Recently, Michele Guida, et al. further put forward a sandwich leading edge structure, the two layers of panels of the sandwich structure adopting the FML composite material and the metallic material respectively, and the core layer being a honeycomb. In the process of the experiment, a bird of 8 pounds is used to strike the structure at a speed of 250 knots, and the leading edge is not broken down, but the entire structure is deformed tremendously. It can be seen that the manufacture expenses of existing structure designs are extremely high however the entire structure is either broken down or deformed tremendously and the effect of anti-bird strike is not satisfactory.
In order to overcome the defects of large deformation and damage and high cost in the prior art of the anti-bird strike of the aircraft structure, the Northwestern Polytechnical University puts forward a horizontal tail leading edge capable of enhancing anti-bird strike performance of aircraft in the Chinese patent application for invention with the application No. 201010554079.4. As shown in FIGS. 1 and 2, the horizontal tail leading edge comprises a leading edge skin 1, a honeycomb core layer 2, a reinforcement 3 located at the horizontal tail leading edge and a wing underlayer 4. The honeycomb core layer 2, the leading edge reinforcement 3 and the wing underlayer 4 are all spanwisely arranged between respective spans inside the wing leading edge. The leading edge reinforcement 3 takes on a shape of triangular prism, and one angle of this leading edge reinforcement is located at the front end of the wing leading edge. The upper honeycomb core layer and the lower honeycomb core layer each take on a shape of a parallelogram and are fixed to the upper and lower inner surfaces of the leading edge skin respectively. One beveled edge of the upper honeycomb core and one beveled edge of the lower honeycomb core both match with one lateral surface of the leading edge reinforcement. The wing liner is fixed to the two honeycomb cores and the surface of the leading edge reinforcement. After the above horizontal tail leading edge structure is struck by a bird, although the segmentation of the bird serves the purpose of protecting the wing liner, this structure has the following defects: the lower honeycomb core is made of a soft material, and suffers a very large compressive deformation under the action of the powerful impact force of the bird, so that the support stiffness of the leading edge skin becomes small, which results in invalidation of the leading edge skin. As can be seen, the skin becomes invalid mainly for the reason that the support stiffness of the skin is reduced, and the invalidation of the leading edge skin will severely influence the aerodynamic performance of the horizontal tail in the flying process. Thus, by a comprehensive consideration of the designs of the anti-bird strike performance and the aerodynamic performance, the applicability of this horizontal tail leading edge capable of enhancing the anti-bird strike performance of the aircraft is not strong.